Structure and Property of Foam Glass-Ceramic Prepared by Copper Tailings

Large-scale reuse of copper tailings can mitigate environmental hazards and recover strategic elements; this work investigates the feasibility of producing foam glass-ceramics with high copper-tailing content (>70 wt%) by tuning the CaO/SiO2 ratio to couple melt viscosity and crystallisation. The comprehensive utilisation of these tailings helps mitigate environmental pollution and enhance resource efficiency. In this study, foam glass-ceramics with varying CaO/SiO2 ratios were synthesised through melt quenching followed by foaming heat treatment. The effects of different CaO/SiO2 ratios on the foaming behaviour, crystallisation, and microstructure were investigated using DSC, FTIR, viscosity, XRD, SEM, and CT. The results indicate that increasing the CaO/SiO2 ratio disrupts the three-dimensional network structure of the glass, which lowers the glass viscosity and influences the bubble size and distribution in the foam glass-ceramics. Additionally, the increased CaO content promotes crystal precipitation and enhances the compressive strength of the foam glass-ceramics. At a CaO/SiO2 mass ratio of 0.22, the foam glass-ceramics exhibited the lower bulk density (240 kg/m3) and thermal conductivity (0.07 W/m·K). The materials also demonstrated good water absorption and compressive strength. This study highlights the potential of using copper tailings in foam glass-ceramics to improve their overall performance, offering promising energy-saving and environmentally friendly solutions.